Bus error (Core Dumped)

Hey everyone,

I am writing a basic program titled, "LMC.c" that takes the contents from a file "LMC.s", and outputs them into another file "LMC.o"

Here is the input file, LMC.s

Code:

INP 00
STO 90
INP 00
ADD 90
OUT 00
STOP 00

Then here is the program that reads the input file, LMC.c

Code:

#include<stdio.h>   
#include<string.h>   

int main()
{
	FILE *input,*output; 
	char opcode[5],address[5]; 
	char binopcode[10], binaddress[10];
	int i;

	/* the following codes open the file for reading and the file for output */
	input = fopen("LMC.s","r");
	output = fopen("LMC.o","w");



	while(fscanf(input,"%s %s",opcode,address)!=EOF)
		{
			printf("Opcode: %s \t\tAddress: %s\n",opcode,address);		

		if(strcmp(opcode, "INP") == 0) 
		{
			strcpy(binopcode,"10000000");
			strcpy(binaddress," ");
		}
		else if(strcmp(opcode,"STO") == 0) 
		{
			strcpy(binopcode,"00000011");
			strcpy(binaddress,"01011010");
		}
		else if(strcmp(opcode,"ADD") == 0) 
		{
			strcpy(binopcode,"00000001");
			strcpy(binaddress,"01011010");
		}
		else if(strcmp(opcode,"OUT") == 0) 
		{
			strcpy(binopcode,"01000000");
			strcpy(binaddress,"");
		}
		else if(strcmp(opcode,"STOP") == 0) 
		{
			strcpy(binopcode,"00000000");
			strcpy(binaddress,"");
		}
		/* now put the results to the output file */

		fprintf(output,"%s %s\n",binopcode,binaddress);
		printf( "%s %s\n",binopcode,binaddress);
		

		} /*end while*/

	
	fclose(output);
	fclose(input);
		
	return 0;
	}

I cannot get it to output the file into "LMC.o" though. I keep getting a "Bus error (core dumped)" when I compile it. Any suggestions why this might be?

Thanks,

MATT

You get that error during the compilation or running your program? Can your program do anything correctly other than write to that file (can it read the input)?

http://www.cplusplus.com/ref/cstdio/fopen.html

You should check for the success of this function as it is a very likely source of errors.

i get the error during compilation, yes. There are no other errors during compilation. It does not create the LMC.o file at all... so I guess Im kinda stuck

Okay, the compilation (or really, the build) process is the proces in which you turn your code into a program. Then, you have the ability to run your program after this happens. I get the feeling that you are actually running your program, that the error is seperate from the compilation process, and that it stems from you not checking the return values of fopen. Would you mind verifying these hypotheses?

Yes, Im sorry. I wasnt thinking right.

The program compiles perfectly. But when I run it, I get the Bus error. Thanks for straightening my out, lol

so with that being said.... any one have any new input to help me out here?

Check your file handles for null values.

Originally Posted by Tonto

Check your file handles for null values.

Im not quite sure what that means. im fairly new to programming....

Would you care to expand?

Code:

	input = fopen("LMC.s","r");
	output = fopen("LMC.o","w");

Code:

if ((input = fopen("LMC.s", "r")) == NULL)
{
    perror("input file");
    exit(1);
}
if ((output = fopen("LMC.o", "w")) == NULL)
{
    perror("output file");
    exit(1);
}

I prefer the following, since it compacts error handling code:

Code:

FILE *input = fopen("LMC.s","r");
FILE *output = fopen("LMC.o","w");

if (input == NULL || output == NULL)
{
  printf("error opening file: input %p output %p\n", (void *)input, (void *)output);
  return 1;
}

I know, just preference

sure you could do that, but since fopen sets errno, perror is alot better than just printf, gives you the reason why there was an error. ie. no such file, invalid permission etc.